1. Field of the Invention
The present invention relates generally to automatic dialing apparatus and a method of automatic dialing. More particularly, it relates to an automatic dialing apparatus and a method of converting a telephone number, previously registered, to a corresponding tone signal to generate the same automatically.
2. Description of the Background Art
A conventional automatic dialing apparatus comprises a storage device provided in a telephone set or a separate electronic device. I can store a number of telephone numbers and other related information such as addresses and names, and a function to convert the stored information to their corresponding tone signals. When any desired one of a plurality of previously registered telephone numbers is called by operating a search key, the corresponding tone signal is outputted by operating a dial out key without pressing a numeral key, thereby to carry out automatic dialing.
A telephone number includes an area code number, a local code number and a subscriber's number. Therefore, the area code number, the local code number and a subscriber's number are registered in advance in the automatic dialing apparatus. By first operating the search key to read a desired telephone number and then operating the dialing key, the tone signals each corresponding to the area code number, the local code number, and the subscriber's number are generated. However, when a telephone call is made in the same city, (i.e., the area of the same area code number), the tone signal of the area code number need not be generated. Therefore, in the conventional automatic dialing apparatus, a discriminating code called a local code mark is inputted between the area code number and the local code number in a registration of the telephone number. Thus, when a telephone call is made in the same city, the area code number is cancelled by operating a cancel key, thereby to generate a tone signal corresponding to the local code number and the subscriber's number.
Recently, an increased number of offices and companies are employing a so-called dial-in system, which allows direct dialing without passing through a switchboard. Each of the telephone numbers given to the telephone sets provided in such offices and companies have the same area code number, and local code number but each different subscriber's number. Thus, it is desirable that after each different subscriber's number is registered in association with the same area code number and local code number and then the tone signal corresponding to the area code number and local code number are generated, a tone signal corresponding to each of the desired subscribers, numbers is generated.
However, in the conventional automatic dialing apparatus, the local code mark is fixedly set between the area code number and the local code number as described above. Thus, an arbitrary number cannot be selected from a series of telephone numbers when necessary. Accordingly, even if each of the telephone numbers comprises the same area code number and local code number, automatic dialing should be carried out by registering each of the telephone numbers in association with the area code number and the local code number so as to generate the tone signal corresponding to the area code number and local code number and subscriber's number without employing the local code mark, or to generate the tone signal corresponding to the local code number and subscriber's number by employing the local code mark. Therefore, the conventional automatic dialing apparatus has the disadvantage of inefficiency.